Ammonia Contact Scrubber with Acid Circulation Loop
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Solution Overview
Problem
Existing ammonia removal systems for fuel cells are large, costly, and require frequent maintenance, as they struggle to efficiently remove ammonia from fuel streams while maintaining performance over long periods without significant size reduction or cost optimization.
Innovation Solution
An ammonia contact scrubber system with an acid circulating loop that directs liquid acid solution through a support material in a counter-flow configuration, enhancing ammonia removal efficiency and reducing the required volume of acid and scrubber size, while incorporating sensors for timely acid replacement to prevent breakthrough.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional ammonia scrubber uses a static bed of phosphoric acid on support material, then ammonia removal is achieved, but the scrubber becomes large, bulky, and excessively costly to provide acceptable ammonia removal for extended periods
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static bed of phosphoric acid to a dynamic circulating liquid acid system. The acid is continuously pumped through the support material and returned to the holding tank, creating a moving reactive medium that increases contact efficiency with ammonia in the fuel stream. This dynamic approach allows for more effective ammonia removal in a compact scrubber volume, resolving the contradiction between reliability and size.
2Productivity
If phosphoric acid is converted to ammonium dihydrogen phosphate during ammonia removal, then ammonia is absorbed, but the capacity for removal is limited and requires frequent scrubber replacement or service
Solution Approach 1:
The patent applies the discarding and recovering principle by continuously circulating the phosphoric acid through the scrubber and returning it to the holding tank. This allows the acid to be reused multiple times rather than being discarded after a single pass. The circulating system maintains acid capacity for ammonia removal over extended operational periods, resolving the contradiction between productivity and duration of action.
3Duration of action of stationary object
If the scrubber is designed to remove ammonia for five to ten years without replacement, then long-term operation is achieved, but the scrubber must be unacceptably large and costly
Solution Approach 1:
The patent applies the continuity of useful action principle by implementing a continuous circulation loop for the phosphoric acid. The acid is constantly pumped through the support material and returned to the holding tank, ensuring continuous contact with ammonia in the fuel stream. This continuous action maintains effective ammonia removal capacity over long service intervals without requiring an oversized scrubber, resolving the contradiction between duration of action and device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves up to ten times more efficient ammonia removal per unit volume of acid, reducing the overall system size and maintenance needs, allowing for longer operation without high-frequency replacements and enabling broader fuel specifications for fuel cells.
Implementation Method 1
the ammonia is absorbed on the support material and reacts with the phosphoric acid
Implementation Method 2
H3PO4+NH3→(NH4)H2PO4
Implementation Method 3
a bed of support material soaked with acid
Data Source
AI summary
An ammonia contact scrubber system (10) for removing ammonia from a fuel stream for a fuel cell (16) includes a contact scrubber (12) having a scrubber fuel inlet (14) and a scrubber fuel exhaust (20) for directing flow of the fuel stream through support material (24) within the scrubber (12) and into the fuel cell (16). An acid circulating loop (26) has an acid holding tank (28) holding a liquid acid solution (30), an acid feed line (32) secured in fluid communication between the holding tank (28) and a scrubber acid inlet (36) of the contact scrubber (12), an acid return (38) for returning the acid solution from the scrubber (12) to the acid holding tank (28), and an acid circulation pump (42) for pumping the acid solution (30) through the acid circulating loop (26) and through the support material (24) within the scrubber (12).